In regard to your first point, most anthropogenic greenhouse gases are well-mixed in the troposphere, meaning that their average concentrations don't vary all that much no matter where you are (on landscape scales and above). Climate change is regionally diverse mostly because the way in which elevated anthropogenic greenhouse gas concentrations interact with the most important greenhouse gas of all (water vapor), as well as atmospheric and oceanic circulation patterns. Urban heat island effects are a different, much more local phenomenon that is negligible on the global scale.
Re: your second point, the problem is the rate of change we are experiencing, which is extremely rapid - too rapid for many biota to adjust and respond to, especially given all the other stresses that are acting on them and depressing their resilience. Globally, we are talking of orders of magnitude faster than what most species we currently share this planet with have experienced in their recent evolutionary history.
Climate change, and especially climate change ecology, is about as intuitive as quantum physics. When you have a heart attack, you trust a doctor who went through years of medical school, residency and practice to stabilize you and save your life. You don't second-guess every incision he makes during your bypass surgery even if it "doesn't seem to make sense". Does he make mistakes from time to time? Sure, but in general he knows exactly what he needs to do and does just that.
The same applies to topics like climate change - don't presume you know better than those of us who have worked on it nearly every day of our lives for many years because it "doesn't seem to make sense". And by "us", I don't mean talking heads on Fox News and CNN working for the PR branch of some nutjob advocacy organizations or Al Gore or James Inhoffe (or whatever his name is).
